The findings of the research do suggest that combining sirolimus with grapefruit juice may achieve a successful “trade-off” between effectiveness and reduced side effects. However, the researchers are clear that further research must be done to develop these preliminary findings.

Therefore, headlines claiming that grapefruit juice "boosts cancer drugs" are both misleading and irresponsible. This was a carefully controlled trial, looking at a single medication, that employed rigorous safety protocols.

Encouraging people to mix grapefruit juice with both prescription and non-prescription drugs could lead to overdoses, which could be dangerous. Cancer patients should not alter their current medication dosages or start drinking grapefruit juice based on this research.

And:

The media reports failed to give clear warnings about the potential
dangers of anyone drinking grapefruit juice while taking certain
medications, due to its ability to strengthen the drug’s dose.

The Express’s headline was particularly misleading as it implied that
all cancer drugs would benefit from being combined with grapefruit
juice. In fact, the researchers were only looking at a single drug, and
even then, this medication is not widely used to treat cancer.

The reports may lead some cancer patients to think that reaching for
the juice is a good or at least harmless idea. However, drinking
grapefruit juice while taking medication is potentially dangerous. NHS
Choices specifically states that if you are taking immunosuppressant
medications such as sirolimus, you should never drink grapefruit juice
without consulting your doctor.